Researchers Evaluate Insects for Biodiesel Production

As a major lignocellulosic biomass, crop residues are considered as feedstock for biofuel production. However, large-scale application of this biofuel process has been facing obstacles. To meet the growing demands for food, feed, and energy as the global population continues to grow, certain kinds of insects have been mentioned as a source of protein and fat.

Hui Wang of Huazhong Agricultural University in China tested a two-stage biorefinery process. The first –stage includes corn stover degradation by yellow mealworm (Tenebrio molitor L.), followed by a second stage that uses black soldier fly (Hermetia illucens L.) to consume the residues produced during the first stage.

These two insect-based biorefinery yielded 8.50 g of insect biomass with a waste dry mass reduction rate of 51.32%. It resulted in 1.95 g of crude grease from larval biomass that produced 1.76 g biodiesel, 6.55 g protein, and 111.59 g biofertilizer. The conversion rate of free fatty acids of crude grease into biodiesel reached 90%. The components of cellulose, hemicellulose, and lignin contained in corn stover were hydrolyzed effectively.

These findings demonstrate that successive co-conversion of corn stover by insects possessing different feeding habits could be an option for efficient use of lignocellulosic resources, and presents a solution to crop residues management, energy supply, and animal feed demand.